Currently, the conventional cases for the switch mostly adopt the assembling method as shown in FIG. 1, in which a tenon and a trough respectively on a cover and a base are employed to mutually engage with each other for assembling, and inside the case, an accommodating space will be formed for positioning the switching unit of the switch. However, the disadvantages are as followed. First, an interval between the tenon and the trough might cause a loose combination of the cover and the base. Second, an interval still might exist at the junction interface between the cover and the base so that moisture which may damage the conductor portion of the switching unit can easily get into the switch case. Third, the cost for molding the cooperated tenon and trough is high, which does not conform to the economic principle.
Therefore, FIG. 2 which shows a sectional drawing of a conventional switch provides another preferred method. As shown, an adhesive is adhered at the junction interface between the cover and the base for fixing thereof and simultaneously preventing the moisture from getting into the inner space so that the conductor portion of the switching unit may not be damaged thereby. Further, this method also benefit by the low cost. However, the adhesive actually has some disadvantages. Referring to the adhering portion shown in FIG. 2, because the adhesive is adhered to a flat plane, a leakage might be produced, so that except the adhesive is not easy to spread, the adhesive may also be extruded by the junction between the cover and the base so as to have an overflow inside or outside the case. If the leakage present at the outer surface of the switch, other components around the switch might be influenced, and if the leakage overflows into the inner portion of the switch, the switching unit therein might be significantly influenced, for example, the electric contact of the switching unit might be influenced, even be spoiled, so as to reduce the yield and also increase the cost.
References incorporated therein are R.O.C. Patent Publication Nos. 531036, 515561 and 458358, which all relate to switches utilizing an engaging portion for combining the cover and the base.